JP2008025578A5 - - Google Patents

Claims (11)

A turbomachine centrifugal compressor impeller downstream cavity ventilation system, wherein the downstream cavity is defined by a downstream side surface of the impeller and a downstream annular end piece of an annular diffuser disposed at the outlet of the centrifugal compressor. And venting by taking air from the outlet of the centrifugal compressor, the ventilation system comprising branch means fixedly attached to the downstream cavity of the impeller, the branch means being taken from the outlet of the compressor The air is diverted along the annular end piece of the diffuser to the inlet in the downstream cavity of the impeller and the ventilation air from the downstream portion of the downstream cavity is diverted so that the ventilation air flows along the downstream side of the impeller. A system that flows from the inside to the outside in the radial direction.   The branching means includes an annular metal plate fixedly attached to a fixing means at the downstream end of the annular end piece of the diffuser in the downstream cavity of the impeller, and the annular metal plate extends from the fixing means to the impeller. The system of claim 1, wherein the system extends upstream along a downstream side of the compressor and terminates in the vicinity of an air extraction means for extracting air from a compressor outlet.   The branching means includes a second annular metal plate fixedly attached to the fixing means at the downstream end of the annular end piece of the diffuser, and the second annular metal plate extends from the fixing means to the annular end piece of the diffuser. The system according to claim 1, wherein the system extends upstream substantially parallel to and terminates in the vicinity of an air extraction means for extracting air from an outlet of the compressor.   The system according to claims 2 and 3, wherein the upstream end of the second annular metal plate is disposed radially outside the upstream end of the first annular metal plate.   The system of claim 4 wherein the downstream side of the impeller supports an annular element that branches off the flow that extends as a protrusion into the downstream cavity between the upstream ends of the two annular metal plates.   The first annular metal plate forms an annular passage for ventilation air with the downstream side surface of the impeller, and the ventilation air is formed between the second annular metal plate and the end piece of the diffuser. The system according to any one of claims 3 to 5, wherein the system is in communication with the annular passage at the downstream end.   The second annular metal plate is inside the downstream cavity, and the annular passage formed by the second annular metal plate with the annular end piece of the diffuser is supplied with air taken from the outlet of the compressor. 6. The system according to 6.   The second annular metal plate is outside the downstream cavity, and the annular passage formed by the second annular metal plate with the annular end piece of the diffuser is supplied with air exiting the diffuser. system.   The system of claim 2, wherein the annular metal plate defines an annular passage along with the downstream side of the impeller that is supplied with air drawn from the ventilating air injection circuit at the downstream end.   Ventilation air injection means is included on the downstream side of the impeller, and the air flow exiting the injection means is directed in the direction of rotation of the impeller, the injection means being driven by the second annular metal plate and / or the annular end piece of the diffuser 10. A system according to any one of claims 3 to 9, which is supported.   A turbomachine comprising the ventilation system according to claim 1.